R/V Ronald H. Brown Daily Summaries

Daily Summary July 22, 2002, DOY = 203

The winds during the period were predominantly from the south through the southeast,
which favored transport from the NY/Boston area. Clear shies and modest wind speeds
also favored photochemical processing and pollution accumulation in the Gulf of Maine.

During the early morning hours the ship transected from a point northeast of the tip
of Cape Anne to a point about 5 nm southeast of the Seabrook nuclear plant. After
daybreak this track was extended closer to shore and shortened to allow for frequent
sampling of a pollution plume located near the northwest end of the nighttime track. The
plume had elevated levels of SO2, NOy, SO2, CO, VOCs. and aerosols. The ship
continued to traverse the plume throughout the day. By the afternoon ozone levels were
approaching 100 ppb and SO4 levels were above 12 ug/m3. The DOE G-1 performed a number of low
passes over the ship in the early afternoon and performed a spiral overhead. The crew reported a
number of pollution layers that were also seen on the ozone/aerosol lidar.

During the early evening hours the ship moved northward just east of the Isles of Shoals
and then made a run to the east to determine the spatial extent of the polluted air mass.